As he stared at the smoke pouring from the ruined skyline of Lower Manhattan, a mechanical voice oddly repeated every 15 minutes over the public address system: ''Terminal 4 J.F.K. is a nonsmoking area.''

The building had been open for only four months and there were still no television sets anywhere, so workers turned to a radio to find out what was happening.

''It changed my world quite a bit,'' said Mr. van der Chijs (it rhymes with wise), whose formal title is president and chief executive of Schiphol USA, making him, among other things, the boss of the new $1.4 billion terminal, which is the cornerstone of a $10.3 billion revitalization program under way at the airport. It is the first air terminal in the United States to be built, developed and managed by a private corporation, a subsidiary of Schiphol Group, the operator of the Amsterdam airport, and the only terminal in the United States that is operated by an entity other than an airline or a government agency.

A tall, slim man of 42 -- he keeps trim running and bicycle racing -- attired in an elegant double breasted gray pinstripe suit, Mr. van der Chijs studied law in his native Amsterdam (he conducts business in Dutch on a tiny cellphone), and was a banker in Hong Kong before joining Schiphol, which has an international business in airport management and real estate. The new terminal is the company's beachhead in America, but he finds himself in a somewhat different world than he had imagined.

First, of course, business fell off drastically. The terminal is designed to handle six million passengers a year, but in the immediate aftermath of the attack, business dropped to about 25 percent of normal. It has been slowly building back up, he said, to about three-quarters of the usual volume. ''We are hurting,'' he said.

Then there is the issue of security and new federally mandated baggage inspections that many people fear will make air travel even more of a nightmare. No one, however, wants to get on a plane with someone wearing exploding sneakers.

In terms of security, the new Terminal 4 is pretty much state of the art. It already has three of the big CTX baggage-screening machines, which cost $1 million each and are the size of a small car, with built-in explosive-sniffing technology -- machines that are to be required in all airports by Dec. 31. (There may be quite a scramble, Mr. van der Chijs observed, because factories are now able to turn out only about 85 a year.) There is also a computerized system that connects each piece of checked luggage with a passenger's boarding pass. If a passenger does not get on the airplane, the baggage can be quickly located and removed. No passenger, he said proudly, has to wait more than 15 minutes to get through security checks, while in some airports there have been lines lasting for two or three hours. But Terminal 4 does not yet have Mr. van der Chijs's favorite device, iris-identifying equipment that is used in some places in Europe, which uses a person's eyeball to verify identity.

''This terminal is probably safer than a city,'' said Mr. van der Chijs, who likes to think of airports as small cities in themselves.

OF course, the new terminal was designed long before Sept. 11 made fear such a part of flying. A lot of what went into building Terminal 4 came from lessons learned at Schiphol Airport in Amsterdam, a famously passenger-friendly agglomeration of shops, restaurants, bars and hotels.

''We want to look at it through the eyes of the passenger,'' Mr. van der Chijs said. ''There should be lots of daylight, an open feeling. We have a lot of art. We use our airport knowledge. The airport should be a pleasant place to stay. Especially now, when people may be staying longer.''

So there are glass walls, flooding the building with sunlight. There are wide aisles around the counters of the 40 airlines, from Aer Lingus to World, using the terminal. The concourse with shops and restaurants is before the security checks, so it is open to friends and relatives accompanying passengers, encouraging them to linger. The artwork includes Alexander Calder's ''Flight'' mobile from the old International Arrivals Building, (whose last remnants are still being gobbled up by backhoes outside the windows) and ceramic bas-relief sculptures above the immigration booths depicting New York City street scenes, including Black Israelites haranguing people in Times Square.

''Let me show you something else we learned from Schiphol,'' said Mr. van der Chijs, an impish bad-boy grin breaking his strait-laced demeanor, leading a visitor into the men's room.

On each of the urinals, a black fly had been stenciled several inches above the drain.

''This saves you a lot of cleaning,'' he said happily. ''The male nature is to want to aim at something.''